Brake problem for a 1970 chevy c-10

[hullettamps]

Guys, I had a brake issue that I have never seen before. I have a 1970 Chevy c-10 daily and the brake pedal began to fad and got to where you had to pump the brakes to get any pedal. These are manual brakes and had new pads and the drums turn a few months ago.

I was driving the truck this last weekend when I pulled over to get gas when I heard a pop sound. I though I lost a wheel cylinder, but had no signs of that being the case. No fluid on the back of the tires, and the master cylinder was full. So I thought nothing of it. When I got back in my truck to drive, I pump my pedal to build pressure and the pedal Kicked back for a lack of a better term. Now when you pump the brakes it kicks like a mule....HELP...is this a master cylinder problem? Has anyone experiences this before?
Thanks Clay

 

[GM Tech]

RE: Brake problem for a 1970 chevy

I would pull the wheels and do a brake inspection first. No telling what might be happening. Sounds to me like you might have a restriction of some sort. By the way, pumping the brakes means you
have a problem to start with.

 

[dvalentine]

RE: Brake problem for a 1970 chevy

It is most likely your master cylinder...
Hydraulic valve seats damaged by dirt or fluid contamination. Flush the system with clean brake fluid and replace it.

DVal

 

[83silverado]

RE: Brake problem for a 1970 chevy

BEING AN OLDER VEHICLE, AFTER DOING AN INSPECTION AND FINDING THE CAUSE, IF THE FLUID IS DIRTY, I WOULD RUN DENATURED ALCOHOL THROUGH THE SYSTEM. THEN THROUGHLY BLEED THE SYSTEM WITH NEW FLUID. OLD CONTAMINATED FLUID CAN CAUSE A WHOLE LOT OF PROBLEMS